Image display devices such as television receivers have become thinner recently with thin display elements such as liquid crystal panels or plasma multi-displays replacing conventional cathode-ray tubes. When using a liquid crystal panel as a display element, it is necessary to have a separately provided illumination device as the backlight device, since liquid crystal panels do not emit light on their own.
A backlight device is disclosed in Patent Document 1 having a plurality of LEDs (light sources), light-emitting diode substrates (light source substrates) on which the LEDs are mounted, a substrate support member (chassis) housing the light-emitting diode substrates, and a reflective sheet covering the light-emitting diode substrates and the substrate support member. In this backlight device, lenses that cover each LED individually are provided, and first holes for inserting these lenses are formed in the reflective sheet. Furthermore, in this backlight device, third holes are formed in the reflective sheet and fitting holes are formed in the light-emitting diode substrates. A shaft (rivet) that goes through these third holes and fitting holes and that attaches to the substrate support member is also provided. The head of the shaft is larger in diameter than the third holes, and the inner surface of the shaft faces the vicinity of the third holes in the reflective sheet; therefore, it is possible to prevent the reflective sheet from tilting away from the light-emitting diode substrate.